My teakettle is moist for hours, some of my dishes are moist for hours, they don't smell like mildew. I'm in the bone dry south bay in a warm house

My guess is water is getting trapped somewhere in the device's Chinesium crevices, or maybe they found a way to make plastic cheaper by making it susceptible to mold.

Every cool-mist humidifier has this problem. Use one of the Vicks vaporizers that boils the water if you don't want to deal with it.

Ours just runs until dry. Pretty sure it’s ultrasonic but it’s cheap and there’s never been a smell. Those are the joys of living someplace you really need a humidifier. Water just disappears.